gastrula


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gastrula

 [gas´troo-lah]
an embryo in the stage following the blastula stage; the simplest type consists of two layers of cells, the ectoderm and entoderm, which have invaginated to form the archenteron and an opening, the blastopore.

gas·tru·la

(gas'trū-lă),
The embryo in the stage of development following the blastula or blastocyst; in lower forms with minimal yolk, it is a simple double-layered structure consisting of ectoderm and endoderm enclosing the archenteron, which opens to the outside by way of the blastopore; in forms with considerable yolk, the configuration of the gastrula is greatly modified owing to the persistence of the yolk throughout the gastrulation process. In human embryos, the gastrula stage occurs in the third week as the embryonic disk becomes trilaminar.
Synonym(s): invaginate planula
[Mod. L. dim. of G. gastēr, belly]

gastrula

/gas·tru·la/ (gas´troo-lah) the embryo in the stage following the blastula or blastocyst; the simplest type consists of two layers of cells, the ectoderm and endoderm, which have invaginated to form the archenteron and an opening, the blastopore. In human embryos the gastrula stage occurs during the third week, as the embryonic disc becomes trilaminar, establishing the ectoderm, mesoderm, and endoderm.

gastrula

(găs′trə-lə)
n. pl. gastru·las or gastru·lae (-lē′)
An embryo at the stage following the blastula, after the movement of cells results in the formation of the three germ layers, ectoderm, mesoderm, and endoderm.

gas′tru·lar (-lər) adj.

gastrula

[gas′troo͡lə]
Etymology: Gk, gaster, stomach
the early embryonic stage formed by the invagination of the blastula. The cup-shaped gastrula consists of an outer layer of ectoderm and an inner layer of mesentoderm that subsequently differentiate into the mesoderm and endoderm. See also blastula, embryonic layer.

gas·tru·la

(gas'trū-lă)
The embryo in the stage of development following the blastula or blastocyst formation; in the human embryo, the absence of yolk allows for a rapid, direct "putting in place" of the germ layers (ectoderm and endoderm), which are derived from the pluripotential embryonic disc.
[Mod. L. dim. of G. gastēr, belly]

gastrula

The stage in the development of an EMBRYO following the BLASTULA stage when the ECTODERM, ENDODERM and primitive GUT have developed.

gastrula

a stage in embryonic development in which the BLASTULA has invaginated, so giving rise to a two-layered embryo by a process of gastrulation. see ARCHENTERON.

gastrula

an embryo in the stage following the blastula stage; the simplest type consists of two layers of cells, the ectoderm and entoderm, which have invaginated to form the archenteron and an opening, the blastopore.
References in periodicals archive ?
Why does not FGF signaling activate ZicL expression in the brain cells before the gastrula stage?
Thus the transition towards an aerobic metabolism at gastrula stage seems to support also the construction that multicellularity has its origin in the anoxic world that is over 2 billion years ago.
The spherical shape began to change form and adopt a fig-fruit shape between the gastrula and neural stages (Fig.
Early gastrula stage; at this stage the blastoderm started invading and slowly spread over the yolk in the form of a thin layer ((Figure -1 C).
At S3, we observed the formation of the gastrula, with the emergence of a thin organic matrix on the vegetative pole of the embryo that will give rise to the embryonic shell (proto-shell).
Stage Y&K Description 1 14 Late gastrula 2 16 Head fold 3 17 Optic vesicle 4 20 Optic cups 5 21 Auditory placodes 6 22 Lens 7 23-25 Otoliths, heartbeat, black pigment in retina and iris is strongest in periphery.
The embryo showed embryonic ectoderm and endoderm, it now had reached the gastrula stage.
Embryos in the gastrula stage will be treated with dieldrin at concentrations ranging from 0.
Use an open paper clip to cut through the center of the gastrula to show the three different layers.
This conclusion is supported by a shift in mitochondrial enzymes toward aerobic metabolism at the gastrula stage (Lovtrup-Rein and Nelson 1982).